An integrated optic frequency translator for microwave lightwave systems

A novel integrated optic component that performs a microwave frequency translation of an optical wave is presented. Its principle of operation and characteristics are derived from a perturbation analysis of the supermode propagation in a Y-fed directional coupler subjected to an electrooptic effect associated with a propagating microwave field. It is found that under appropriate values of the microwave field amplitude and interaction length, a very efficient conversion of optical power can be achieved. The optimum frequency shift of this transfer is controlled through the coupling length of the directional coupler. An approximate analytical solution of the coupled mode equations, which considers only the coupling between the two spectral components of the supermodes that are phase matched, has been performed.